Zhang, Lei; Chai, Xiaoyun; Wang, Baogang; Yu, Shichong; Hu, Honggang; Zou, Yan; Zhao, Qingjie; Meng, Qingguo; Wu, Qiuye Bioorganic and Medicinal Chemistry Letters, 2013, vol. 23, # 18 p. 5057 - 5060 doi: 10.1016/j.bmcl.2013.07.042